Understanding of neuromuscular diseases is founded on careful clinical observation, electrodiagnostic studies and pathology. This protocol has been developed to learn more about established diseases, to characterize new diseases, to assess current methodologies and technologies, and to refine old methods and develop new ones. Studies initiated under this protocol include: a. The effect of varying the detection threshold on interference pattern analysis in healthy subjects patients with primary muscle disease. b. The use of mixed nerve action potentials (MNAPs) in patients with chronic inflammatory demyelinating neuropathy (CIDP), including the use of monopolar recording to detect temporal dispersion. c. The use of medial plantar nerve action potentials (NAPS) in patients with axonal neuropathies.